WO2011159809A2

WO2011159809A2 - Soil reinforcing element for a mechanically stabilized earth structure

Info

Publication number: WO2011159809A2
Application number: PCT/US2011/040543
Authority: WO
Inventors: Thomas P. Taylor
Original assignee: T & B Structural Systems Llc
Priority date: 2010-06-17
Filing date: 2011-06-15
Publication date: 2011-12-22
Also published as: US20110311317A1; US8734059B2; CA2798147A1; WO2011159809A3; AU2011268418A1

Abstract

A soil reinforcing element for use in a mechanically stabilized earth structure is disclosed. The soil reinforcing element may include a pair of longitudinal wires extending substantially parallel to each other and having a connection end. A plurality of transverse wires is coupled to the pair of longitudinal wires and laterally-spaced from each other, thereby forming a welded wire gridworks. To increase the tensile capacity of the soil reinforcing element and also improve pullout valued from the backfill, the soil reinforcing element is made of positively deformed wire or bar stock. An end connector is coupled to the connection end and facilitates connection of the soil reinforcing element to a vertical facing.

Description

SOIL REINFORCING ELEMENT FOR A

MECHANICALLY STABILIZED EARTH STRUCTURE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The application claims priority to U.S. Pat. App. No. 13/012,680 entitled "Soil Reinforcing Element for a Mechanically Stabilized Earth Structure," which was filed on January 24, 201 1 as a continuation-in-part of co-pending U.S. Pat. App. No. 12/837,347, entitled "Mechanically Stabilized Earth Welded Wire Facing Connection System and Method," which was filed on July 15, 2010, which was a continuation-in-part application of U.S. Pat. App. No. 12/818,01 1 , entitled "Mechanically Stabilized Earth System and Method," and filed on June 17, 2010. The contents of each priority application are hereby incorporated by reference to the extent consistent with the disclosure.

BACKGROUND OF THE DISCLOSURE

[0002] Retaining wall structures that use horizontally positioned soil inclusions to reinforce an earth mass in combination with a facing element are referred to as mechanically stabilized earth (MSE) structures. MSE structures can be used for various applications including retaining walls, bridge abutments, dams, seawalls, and dikes.

[0003] The basic MSE implementation is a repetitive process where layers of backfill and horizontally-placed soil reinforcing elements are positioned one atop the other until a desired height of the earthen structure is achieved. Typically, grid-like steel mats or welded wire mesh are used as soil reinforcing elements. In most applications, the soil reinforcing elements consist of parallel, transversely-extending wires welded to generally parallel, longitudinally-extending wires, thus forming a grid-like mat or structure. Backfill material and the soil reinforcing mats are combined and compacted in series to form a solid earthen structure that takes the form of a standing earthen wall.

[0004] In some instances, the soil reinforcing elements can be attached or otherwise coupled to a substantially vertical wall either forming part of the MSE structure or being offset a short distance therefrom. The vertical wall is typically made either of concrete or a steel wire facing and not only serves to provide tensile resistance to the soil reinforcing elements but also prevents erosion of the MSE structure. The soil reinforcing elements extending from the compacted backfill may be attached directly to a vertical wall of the facing in a variety of configurations.

[0005] Although there are several different configurations and types of soil reinforcing elements known in the art, including different materials from which they are made, it nonetheless remains desirable to find improved configurations or materials that provide greater resistance to shear forces inherent in such structures. SUMMARY OF THE DISCLOSURE

[0006] Embodiments of the disclosure may provide a mechanically stabilized earth (MSE) structure. The MSE structure may include a vertical facing disposed adjacent an earthen formation, and a soil reinforcing element coupled to the vertical facing and extending into the earthen formation, the soil reinforcing element comprising a plurality of transverse wires coupled to at least two longitudinal wires having lead ends that converge, wherein the lead ends have deformations defined thereon. The MSE structure may further include an end connector welded to the lead ends of the longitudinal wires, the end connector being configured to couple the soil reinforcing element to the vertical facing.

[0007] Embodiments of the disclosure may further provide a method for coupling an end connector to a soil reinforcing element. The soil reinforcing element may have a plurality of transverse wires coupled to at least two longitudinal wires having lead ends that converge. The method may include placing a portion of the end connector between the lead ends of the soil reinforcing element, the soil reinforcing element defining a plurality of deformations thereon. The method may further include welding the portion of the end connector to the lead ends, whereby the plurality of deformations provides a more robust weld.

[0008] Embodiments of the disclosure may further provide a soil reinforcing element. The soil reinforcing element may include a pair of longitudinal wires extending substantially parallel to each other and having a connection end. The soil reinforcing element may further include a plurality of transverse wires coupled to the pair of longitudinal wires and laterally- spaced from each other, the pair of longitudinal wires and the plurality of transverse wires being made of positively deformed wire or bar stock. An end connector may be coupled to the connection end, thereby taking advantage of the positively deformed wire and its ability to create a more effective resistance weld.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is an isometric view of an exemplary system of constructing a mechanically stabilized earth structure, according to one or more aspects of the present disclosure.

[0010] Figure 2A is an isometric view of an exemplary wire facing element, according to one or more aspects of the present disclosure.

[0011] Figure 2B is a side view of the wire facing element shown in Figure 2A.

[0012] Figure 3 is an isometric view of a soil reinforcing element used in the system shown in Figure 1 , according to one or more aspects of the present disclosure.

[0013] Figure 4 is a plan view of the system of constructing a mechanically stabilized earth structure, according to one or more aspects of the present disclosure. [0014] Figure 5 is a side view of the connection apparatus for connecting at least two lifts or systems, according to one or more aspects of the present disclosure.

[0015] Figure 6A is an isometric view of another system of constructing a mechanically stabilized earth structure, according to one or more aspects of the present disclosure.

[0016] Figure 6B is a side view of a soil reinforcing element used in the system shown in

Figure 6A, according to one or more aspects of the present disclosure.

[0017] Figure 7 is an isometric view of an exemplary soil reinforcing element, according to one or more aspects of the present disclosure.

[0018] Figure 8 is an isometric view of another exemplary soil reinforcing element, according to one or more aspects of the present disclosure.

[0019] Figure 9 is an isometric view of another exemplary soil reinforcing element, according to one or more aspects of the present disclosure.

DETAILED DESCRI PTION

[0020] It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.

[0021] Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Additionally, in the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to." All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term "or" is intended to encompass both exclusive and inclusive cases, i.e., "A or B" is intended to be synonymous with "at least one of A and B," unless otherwise expressly specified herein.

[0022] Referring to Figure 1 , illustrated is an isometric view of an exemplary system 100 for erecting an MSE structure. In brief, and as will be described in more detail below, the system 100 may include one or more wire facings 102 stacked one atop the other and having one or more soil reinforcing elements 202 coupled thereto and extending into fields of backfill 103. One or more struts 1 18 may also be coupled to each wire facing 102 for structural reinforcement and adapted to maintain each wire facing 102 in a predetermined angular configuration. The backfill 103 may be sequentially added to the system 100 in a plurality of layers configured to cover the soil reinforcing elements 202, thereby providing tensile strength to the wire facings 102 and preventing the wire facings 102 from bulging outward. A more detailed discussion of these and other elements of the system 100 follows herewith.

[0023] Referring to Figures 2A and 2B, each wire facing 102 of the system 100 may be fabricated from several lengths of cold-drawn wire welded and arranged into a mesh panel. The wire mesh panel can then be folded or otherwise shaped to form a substantially L- shaped assembly including a horizontal element 104 and a vertical facing 106 or wire facing. In other embodiments, the horizontal element 104 and vertical facing 106 include independent wire meshes that are coupled or otherwise attached at one end, thereby forming the substantially L-shaped assembly,

[0024] The horizontal element 104 may include a plurality of horizontal wires 108 welded or otherwise attached to one or more cross wires 1 10, such as an initial wire 1 10a, a terminal wire 1 10b, and a median wire 1 10c. The initial wire 1 10a may be disposed adjacent and directly behind the vertical facing 106, thereby being positioned inside the MSE structure. The terminal wire 1 10b may be disposed at or near the distal ends of the horizontal wires 108. The median wire 1 10c may be welded or otherwise coupled to the horizontal wires 108 and disposed at a variety of lateral distances between the initial and terminal wires 1 10a,b. As can be appreciated, any number of cross wires 1 10 can be employed without departing from the scope of the disclosure. For instance, in at least one embodiment, the median wire 1 10c may be excluded from the system 100.

[0025] The vertical facing 106 can include a plurality of vertical wires 1 12 extending generally vertical with reference to the horizontal element 104 and laterally-spaced from each other. In one embodiment, the vertical wires 1 12 may be vertically-extending extensions of the horizontal wires 108. In other embodiments, the vertical wires 1 12 may be independent of the horizontal wires 108 where the vertical facing 106 is independent of the horizontal element 104. The vertical facing 106 may also include a plurality of facing cross wires 1 14, including a top-most cross wire 1 16, vertically-offset from each other and welded or otherwise attached to the vertical wires 1 12. The top-most cross wire 1 16 may be vertically-offset a short distance above the last facing cross wire 1 14.

[0026] In at least one embodiment, each vertical wire 1 12 may be separated by a distance of about 4 inches on center from adjacent vertical wires 1 12, and the facing cross wires 1 14 may also be separated from each other by a distance of about 4 inches on center, thereby generating a grid-like facing composed of a plurality of square voids having about a 4" x 4" dimension. As can be appreciated, however, the spacing between adjacent wires 1 12, 1 14 can be varied to more or less than 4 inches to suit varying applications and the spacing need not be equidistant. In one embodiment, the top-most cross wire 1 16 may be vertically-offset from the last facing cross wire 1 14 by a distance X, as will be discussed in more detail below.

[0027] The wire facing 102 may further include a plurality of connector leads 1 1 1 a-g extending from the horizontal element 104 and up the vertical facing 106. In an embodiment, each connector lead 1 1 1 a-g may include a pair of horizontal wires 108 (or vertical wires 1 12, if taken from the frame of reference of the vertical facing 106) laterally- offset from each other by a short distance. The short distance between adjacent horizontal or vertical wires 108, 1 12 to form the connector leads 1 1 1 a-g can vary depending on the particular application, but may generally include about a one inch separation. In one embodiment, each connector lead 1 1 1 a-g may be equidistantly-spaced from adjacent connector leads 1 1 1 a-g along the horizontal element 104 and/or vertical facing 106, and configured to provide a visual indicator to an installer as to where a soil reinforcing element 202 (Figures 1 and 3) may be properly attached to the facing 102. In at least one embodiment, each connector lead 1 1 1 a-g may be spaced from each other by about 12 inches on center. Such relative distances, however, may vary to suit particular applications.

[0028] Still referring to Figures 2A-2B, one or more struts 1 18 may be operatively coupled to the wire facing 102. As illustrated, the struts 1 18 may be coupled to both the vertical facing 106 and the horizontal element 104 at appropriate locations. Each strut 1 18 may be prefabricated with or otherwise include a connection device 120 disposed at each end of the strut 1 18. The connection device(s) may be configured to fasten or otherwise attach the struts 1 18 to both the horizontal element 104 and the vertical facing 106. In at least one embodiment, as can best be seen in Figure 5, the connection device 120 may include a hook that is bent about 180° back upon itself. In other embodiments, the connection device 120 may include a wire loop that can be manipulated, clipped, or otherwise tied to both the horizontal element 104 and the vertical facing 106. As can be appreciated, however, the struts 1 18 can be coupled to the horizontal element 104 and the vertical facing 106 by any practicable method or device known in the art without departing from the scope of the disclosure.

[0029] Each strut 1 18 may be coupled at one end to at least one facing cross wire 1 14 and at the other end to the terminal wire 1 10b. In other embodiments, one or more struts 1 18 may be coupled to the median wire 1 10c instead of the terminal wire 1 10b, without departing from the scope of the disclosure. As illustrated, each strut 1 18 may be coupled to the wire facing 102 in general alignment with a corresponding connector lead 1 1 1 a-g. In other embodiments, however, the struts 1 18 can be connected at any location along the respective axial lengths of any facing cross wire 1 14 and terminal wire 1 10b, without departing from the scope of the disclosure. In yet other embodiments, the struts 1 18 may be coupled to a vertical wire 1 12 of the vertical facing 106 and/or a horizontal wire 108 of the horizontal element 104, respectively.

[0030] The struts 1 18 are generally coupled to the wire facing 102 before any backfill 103 (Figure 1 ) is added to the respective layer or "lift" of the system 100. During the placement of backfill 103, and during the life of the system 100, the struts 1 18 may serve as structural reinforcement to prevent the vertical facing 106 from bending or otherwise extending past a predetermined vertical angle. For example, in the illustrated embodiment, the struts 1 18 may be configured to maintain the vertical facing 106 at or near about 90° with respect to the horizontal element 104. As can be appreciated, however, the struts 1 18 can be fabricated to varying lengths or otherwise attached at varying locations along the wire facing 102 to maintain the vertical facing 106 at a variety of angles of orientation. The struts 1 18 may allow installers to walk on the backfill 103 of the MSE structure, tamp it, and compact it fully before adding a new lift or layer.

[0031] Referring now to Figure 3, illustrated is an exemplary soil reinforcing element 202 that may be attached or otherwise coupled to a portion of the wire facing 102 (Figures 2A and 2B) in the construction of an MSE structure. The soil reinforcing element 202 may include at least two longitudinal wires 204 that extend substantially parallel to each other. The longitudinal wires 204 may be joined to one or more transverse wires 206 in a generally perpendicular fashion by welds at their intersections, thus forming a welded wire gridworks.

[0032] In one or more embodiments, lead ends 208 of the longitudinal wires 204 may generally converge and be welded or otherwise attached to a connector 210, or end connector. In at least one embodiment, the connector 210 (exploded in Figure 3 for ease of viewing) may include a coil 212, a threaded rod 214, such as a bolt or a length of rebar, and a nut 216. As illustrated, the coil 212 may include a plurality of indentations or grooves defined along its axial length which provide a more suitable welding surface for attaching the lead ends 208 of the longitudinal wires 204 thereto. For example, where the coil 212 is resistance welded to the lead ends 208, such indentations and/or grooves can result in a stronger weld. In one embodiment, the coil 212 can be a helical or coil spring. In other embodiments, the coil 212 can be another nut or a coil rod that is welded to the longitudinal wires 204. Other exemplary embodiments of the connector 210 contemplated herein are described in co-owned U.S. Pat. No. 6,571 ,293 entitled "Anchor Grid Connector Element," issued on February 1 1 , 2003 and hereby incorporated by reference to the extent not inconsistent with the present disclosure.

[0033] To secure the soil reinforcing element 202 to a portion of the wire facing 102 (Figure 2B), or more particularly the vertical facing 106, the head 218 of the threaded rod 214 may be disposed on the front side of at least two vertical wires 1 12, such as at a connector lead 1 1 1 a. The body of the threaded rod 214 can be extended through the vertical facing 106 and coil 212 and secured thereto with the nut 216 at its end. As illustrated, the head 218 may be prevented from passing through the vertical wires 1 12 or connector lead 1 1 1 a by employing a washer 220 disposed radially about the threaded rod and adapted to provide a biasing engagement with the vertical wires 1 12 or connector lead 1 1 1 a. As the nut 216 is tightened, it forces the coil 212 into engagement, or at least adjacent to, the back side of the vertical facing 106.

[0034] In embodiments where the lateral spacing of adjacent vertical wires 1 12 is such that the connector 210 and a portion of the soil reinforcing element 202 may be able to extend through the vertical facing 106, it is further contemplated to employ a secondary washer or bearing plate (not shown) on the inside or back side of the vertical facing 106. For instance, at least one secondary washer or bearing plate may extend radially around the threaded rod and be disposed axially adjacent the coil 212 and large enough so as to bear on at least two vertical wires 1 12 and prevent the connector 210 and lead ends 208 from passing through the vertical facing 106. Accordingly, the soil reinforcing element 202 may be secured against removal from the wire facing 102 on both the front and the back sides of the vertical facing 106.

[0035] Referring to Figure 4, depicted is a plan view of the system 100 where at least four soil reinforcing elements 202 are coupled to a wire facing 102. As illustrated, the soil reinforcing elements 202 may be attached to the wire facing 102 at one or more connector leads 1 1 1 a-g. In one or more embodiments, soil reinforcing elements 202 may be connected to every connector lead 1 1 1 a-g, every other connector lead 1 1 1 a-g, every third connector lead 1 1 1 a-g, etc. For instance, Figure 4 depicts soil reinforcing elements 202 connected to every other connector lead 1 1 1 a, 1 1 1 c, 1 1 1 e, and 1 1 1 g.

[0036] In one or more embodiments, the terminal wire 1 10b and/or median wire 1 10c may be located at a predetermined distance from the initial wire 1 10a to allow at least one transverse wire 206 of the soil reinforcing element 202 to be positioned substantially adjacent the terminal and/or median wires 1 10b, 1 10c when the soil reinforcing element 202 is secured against the wire facing 102 with the connector 210. Accordingly, corresponding transverse wires 206 may be coupled or otherwise attached to the terminal and/or median wires 1 10b, 1 10c. The transverse wires 206 may be positioned either directly behind or in front of the terminal and/or median wires 1 10b, 1 10c and secured thereto using a coupling device (not shown), such as a hog ring, wire tie, or the like. In yet other embodiments, the soil reinforcing element 202 is secured to only one or none of the terminal and/or median wires 1 10b, 1 10c.

[0037] In embodiments where the soil reinforcing element 202 is not coupled to the terminal or median wires 1 10b, 1 10c, it may be free to swivel in a horizontal plane as generally indicated by arrows A. As can be appreciated, this configuration allows the soil reinforcing elements 202 to swivel in order to avoid vertically-disposed obstructions, such as drainage pipes, catch basins, bridge piles, or bridge piers, which may be encountered in the backfill 103 (Figure 1 ) field.

[0038] As shown in both Figures 1 and 4, the system 100 may further include a screen 402 disposed on the wire facing 102 once the soil reinforcing elements 202 have been connected as generally described above. In one embodiment, the screen 402 can cover all or portions of both the vertical facing 106 and the horizontal element 104. As illustrated, the screen 402 may be placed on substantially all of the vertical facing 106 and only a portion of the horizontal element 104. In other embodiments, however, the screen 402 may be arranged on the wire facing 102 in different configurations, such as covering the entire horizontal element 104 or only a portion of the vertical facing 106. In operation, the screen 402 may be configured to prevent backfill 103 (Figure 1 ) from leaking, eroding, or otherwise raveling out of the wire facing 102. In one embodiment, the screen 402 may be a layer of filter fabric. In other embodiments, however, the screen 402 may include construction hardware cloth or a fine wire mesh. In yet other embodiments, the screen 402 may include a layer of cobble, such as large rocks that are too large to advance through the square voids defined in the vertical facing 106, but are small enough to generally prevent backfill 103 materials from penetrating the wire facing 102.

[0039] Referring again to Figure 1 , the system 100 can be characterized as a lift 105 used in erecting an MSE structure wall to a predetermined height. To reach the required height, a plurality of lifts (e.g., lifts 105a and 105b) may be required. Each lift 105a,b may include the elements of the system 100 as generally described above in Figures 2A, 2B, 3, and 4. While only two lifts 105a,b are shown in Figure 1 , it will be appreciated that any number of lifts may be used to reach a desired height for the MSE structure. As depicted, the first lift 105a may be disposed generally below the second lift 105b and the horizontal elements 104 of each lift 105a,b may be oriented substantially parallel to and vertically- offset from each other. The angle of orientation for the vertical facings 106 of each lift 105a,b may be similar or may vary, depending on the application. For example, the vertical facings 106 of each lift 105a,b may be disposed at angles less than or greater than 90° with respect to horizontal.

[0040] In at least one embodiment, the vertical facings 106 of each lift 105a,b may be substantially parallel and continuous, thereby constituting an unbroken vertical ascent for the facing of the MSE structure. In other embodiments, however, the vertical facings 106 of each lift 105a,b may be laterally offset from each other and form a stepped facing. For example, the disclosure contemplates embodiments where the vertical facing 106 of the second lift 105b may be disposed behind or in front of the vertical facing 106 of the first lift 105a, and so on until the desired height of the MSE wall is realized.

[0041] In one or more embodiments, because of the added strength derived from the struts 1 18, each lift 105a,b may be entirely free from contact with any adjacent lift 105a,b (with exception of the backfill 103). Thus, in at least one embodiment, the first lift 105a may have backfill placed thereon up to or near the vertical height of the vertical facing 106 and compacted so that the second lift 105b may be placed completely on the compacted backfill 103 of the first lift 105a therebelow. Whereas conventional systems would require the vertical facing 106 of the first lift 105a to be securely fastened to the vertical facing 106 of the second lift 105b to prevent its outward displacement, the present disclosure allows each lift 105a,b to be physically free from engagement with each other. This may prove advantageous during settling of the MSE structure. For instance, where adjacent lifts 105a,b are not in contact with each other, the system 100 may settle without causing adverse binding which can potentially diminish the structural integrity of the MSE structure.

[0042] Referring now to Figure 5, other embodiments of the disclosure include engaging the first and second lifts 105a,b in sliding engagement with one another using the connector 210 of the soil reinforcing elements 202. As shown in Figure 5, each lift 105a,b may have a corresponding vertical facing 106a, 106b. The first lift 105a may be disposed substantially below the second lift 105b, with its vertical facing 106a being placed laterally in front of the vertical facing 106b of the second lift 105b. Backfill 103 may be added to at least a portion of the first lift 105a to a first height or distance Y above the last facing cross wire 1 14. The second lift 105b may be disposed on top of the backfill 103, thereby also being placed a distance Y above the last facing cross wire 1 14. As will be appreciated, the first height or distance Y can be any distance or height less than the distance X. For example, the distance Y can be about but less than the distance X, thereby having the backfill 103 level up to but just below the top-most cross wire 1 16 of the vertical facing 106a.

[0043] In order to bring the vertical facings 106a,b of each lift 105a,b into engagement or at least adjacent one another, the threaded rod 214 of the connector 210 may be configured to extend through each vertical facing 106a,b and be secured with the nut 216. In order to ensure a sliding engagement between the first and second lifts 105a,b, the nut 216 may be "finger-tightened," or tightened so as to nonetheless allow vertical movement of either the first or second lift 105a,b with respect to each other. Tightening the nut 216 may bring the coil 212 into engagement with the backside of the vertical facing 106b of the second lift 105b, with the coil eventually resting on the initial wire 1 10a. Tightening the nut 216 may also force the washer 220 into engagement with the vertical facing 106a of the first lift 105a on the opposite side. Tightening the nut 216 may further bring the top-most cross wire 1 16 into engagement with the vertical facing 106b, thereby preventing the outward displacement of the vertical facing 106b. However, in other embodiments, the top-most cross wire 1 16 is not necessarily brought into contact with the vertical facing 106b, but the vertical facing 106b may be held in its angular configuration by the strut(s) 1 18 attached at the upper facing cross wire 1 14 of the vertical facing 106b.

[0044] Placing the second lift 105b a distance Y above the upper facing cross wire 1 14 allows the second lift 105b to vertically shift or translate the distance Y in reaction to backfill 103 settling or thermal expansion/contraction of the MSE structure. Accordingly, the distance Y can be characterized as a distance that the second lift 105b may be able to settle without binding on the first lift 105a and thereby weakening the structural integrity of the MSE system. [0045] Referring now to Figures 6A-6B, depicted is another exemplary embodiment of the system 100 depicted in Figure 1 , embodied and described here as system 600. As such, Figures 6A-6B may best be understood with reference to Figures 1 -5, wherein like numerals correspond to like elements and therefore will not be described again in detail. Similar to the system 100 generally described above, system 600 may include one or more lifts 105a,b stacked one atop the other and having one or more soil reinforcing elements 202 coupled to the wire facings 102. The soil reinforcing elements 202 extend into the backfill 103 which is sequentially added to the system 600 in a plurality of layers configured to cover the soil reinforcing elements 202 and provide tensile strength to each wire facing 102.

[0046] The soil reinforcing elements 202 in system 600, however, may include a different type of connector 210 than that described in system 100, as illustrated in Figure 3 above. For example, any type of threaded rod can be extended through the coil 212 and secured thereto with a nut 216, thereby replacing the threaded rod 214 as generally described with reference to Figure 3. Referring to the exploded view of the connector 210 in Figure 6B, a threaded eye-bolt 602 with a head 604 may replace the threaded rod 214. As illustrated, the head 604 may be a loop having a centrally-defined aperture 605. To secure the soil reinforcing element 202 to a portion of a wire facing 102, or in particular the vertical facing 106 thereof, the head 604 of the eye-bolt 602 may be disposed on the front side of at least two vertical wires 1 12, such as at a connector lead 1 1 1 a, such that the body of the eye-bolt 602 can be extended through the coil 212 and secured thereto with the nut 216 on its opposite end. As illustrated, the loop or head 604 may be prevented from passing through the vertical wires 1 12 or connector lead 1 1 1 a by employing a washer 220 adapted to provide a biasing engagement with the vertical wires 1 12 or connector lead 1 1 1 a on the front side surface of the vertical facing 106. As the nut 216 is tightened, it brings the coil 212 into engagement or at least adjacent to the back side of the vertical facing 106, and the washer 220 into engagement with the vertical wires 1 12 or connector lead 1 1 1 a at the front side.

[0047] In one or more embodiments, the body of the eye-bolt 602 may also be threaded through a second nut 606 adapted to be disposed against the washer 220 on the outside of the vertical facing 106. As illustrated, the body of the eye-bolt 602 can have a non-threaded portion 603 configured to offset the second nut 606 from the head 604 a distance Z when the second nut 606 is fully threaded onto the body. This may allow the head 604 to be laterally-offset a short distance from the vertical facing 106, as shown in Figure 6A.

[0048] As can be appreciated, having the head 604 offset from the vertical facing 106 may provide an attachment means for a laterally offset facing, such as a facing used in two- stage MSE applications. Examples of two-stage MSE applications include co-owned U.S. Pat. App. No. 12/132,750, entitled "Two Stage Mechanically Stabilized Earth Wall System," filed June 4, 2008, and U.S. Pat. App. No. 13/012,607, entitled "Two Stage Mechanically Stabilized Earth Wall System," filed January 24, 201 1 , the contents of each application are hereby incorporated by reference to the extent consistent with the present disclosure. As illustrated, the loop or head 604 may be horizontally-disposed, but may also be vertically- disposed without departing from the scope of the disclosure.

[0049] Referring now to Figure 7, illustrated is an exemplary soil reinforcing element 700, according to one or more embodiments disclosed. The soil reinforcing element 700, and those disclosed in Figures 8 and 9 below, may be used in exemplary MSE structures, such as those described herein. Similar to the soil reinforcing element 202 described with reference to Figure 3 above, the soil reinforcing element 700 may generally include a welded wire grid made of metal and having a pair of longitudinal wires 702 that are disposed substantially parallel to each other and extend horizontally into the backfill 103 (Figures 1 and 6A). In some embodiments, there may be more than two longitudinal wires 702. The longitudinal wires 702 are joined by a plurality of transverse wires 704 laterally-offset from each other along the length of the longitudinal wires 702. In one embodiment, the transverse wires 704 may be arranged generally perpendicular to the longitudinal wires 702, but other angles of relative configuration are also contemplated herein without departing from the scope of the disclosure.

[0050] The transverse wires 704 may be coupled to the longitudinal wires 702 by welds or other suitable attachment means at their intersections, such as with rebar ties. The spacing between each longitudinal wire 702 may be about 2 inches, while the spacing between each transverse wire 704 may be about 6 inches. As can be appreciated, however, the spacing and configuration of adjacent respective wires 702, 704 may vary for a variety of reasons, such as the combination of tensile force requirements that the soil reinforcing element 700 must endure and resist.

[0051] Each longitudinal wire 702 may have a lead end 706 that generally converges toward an adjacent lead end 706. Although a specific angle of convergence Q of the lead ends 706 is shown in Figure 7, it will be appreciated that any angle of convergence Q of the lead ends 706 may be employed without departing from the scope of the disclosure. In one embodiment, the lead ends 706 converge and terminate at a wall end 708 or a connection end of the element 700. The wall end 708 may be configured to receive or otherwise be attached to an end connector 710 adapted to attach the soil reinforcing element 700 to a variety of types of vertical facings (not shown), such as a wire facing, a concrete facing, or a sheet metal facing. Once appropriately secured to the vertical facing and compacted within the backfill 103 (Figures 1 and 6A), the soil reinforcing element 700 provides tensile strength to the vertical facing and prevents any outward movement and shifting thereof.

[0052] The end connector 710 is illustrated as a dashed box since there are numerous end connectors 710 that may be used in conjunction with the soil reinforcing element 700, without departing from the scope of the disclosure.

[0053] The soil reinforcing element 700 may be made of lengths of wire or bar stock that define numerous deformations 712 on the surface thereof. In one embodiment, the deformations 712 are positively defined and extend radially-outward from the surface of each wire 702, 704. The positive deformations 712 may be formed by cold-forming processing, which increases the strength of the wires 702, 704 via strain hardening. Consequently, the positive deformations 712 provide higher tensile capacity yield strength. For example, the tensile capacity of a soil reinforcing element having smooth wires 702, 704 is about 65 ksi, while positively deformed wires 702, 704 provide a tensile capacity that is about 20% greater, or about 80 ksi.

[0054] In other embodiments, the deformations 712 are negatively defined and extend radially-inward from the surface of each wire 702, 704. Wires 702, 704 having negative deformations 712 may include lengths of rebar or similar types of bar stock. Whether positively or negatively defined, however, the deformations 712 also serve to increase the pull-out capacity of the soil reinforcing element 700, whereby it becomes more difficult to pull the soil reinforcing element 700 through compacted soil in the backfill 103 (Figures 1 and 6A).

[0055] Referring now to Figure 8, illustrated is another soil reinforcing element 800, according to one or more embodiments of the disclosure. The soil reinforcing element 800 may be similar in some respects to the soil reinforcing element 700 of Figure 7. Accordingly, the soil reinforcing element 800 may be best understood with reference to Figure 7, where like numerals designate like elements that will not be described again in detail. Unlike the soil reinforcing element 700 of Figure 7, the soil reinforcing element 800 has a connection end where the lead ends 706 generally converge but are not coupled to each other. Instead, the lead ends 706 provide an area where an end connector 710 may be coupled thereto.

[0056] The deformations 712 defined in the surface of the lead ends 706 provide a more effective resistance weld to the end connector 710. For example, the deformations 712 allow the metal in the soil reinforcing element 800 to puddle quicker, thereby requiring less heat and less pressure to generate a solid resistance weld to the end connector 710. Moreover, having deformations 712 defined on the lead ends 706 may eliminate the need to have grooves or indentations on the end connector 710, such as the grooves and indentations shown on the coil 212 in Figures 3 and 6B. Accordingly, one of the end connectors 710 that could be attached to the soil reinforcing element 800 is the connector 210 shown and described in Figures 3 and 6B.

[0057] It will be appreciated that several other types of end connectors 710 may also be coupled to the lead ends 706 of the soil reinforcing element 800. For example, the connection stud disclosed in co-owned U.S. Pat. App. No. 12/479,488 entitled "Mechanically Stabilized Earth Connection Apparatus," filed June 5, 2009 and incorporated herein by reference to the extent not inconsistent with the present disclosure, may be a suitable end connector 710. The connection stud may include a cylindrical body bent to about a 90° angle relative to horizontal, thus forming a vertical portion. The vertical portion may terminate at a head that is noticeably larger than the diameter or cross-section of the vertical portion. The tail end of the body may include indentations or thread markings capable of enhancing the resistance weld to the lead ends 706.

[0058] The connection studs disclosed in co-owned U.S. Pat. App. No. 12/756,898 entitled "Retaining Wall Soil Reinforcing Connector and Method," filed April 8, 2010 and incorporated herein by reference to the extent not inconsistent with the present disclosure, may also be a suitable end connector 710. One disclosed connection stud is created from a one-piece forging process and has a tab that extends from its stem. The stem may be either convex or concave longitudinally and include a plurality of indentations, grooves, or threads defined along its axial length, either cast or otherwise machined into the stem. Another disclosed connection stud is a loop-type connection stud where the tab is generally replaced with a loop or ring. The stem can define axial channels disposed along opposing sides of its axial length, and having a plurality of grooves cast in or otherwise machined therein. Yet another disclosed connection stud is a dual-prong connection stud, where the tab is replaced with a pair of prongs vertically offset from each other and extending axially from the stem. Each prong may define a centrally-disposed perforation, coaxially aligned with each other, and used for connecting the dual-prong connection stud to a facing anchor, for example.

[0059] The connection stud disclosed in co-owned U.S. Pat. App. No. 12/818,01 1 entitled "Mechanically Stabilized Earth System and Method," filed June 17, 2010 and incorporated herein by reference to the extent not inconsistent with the present disclosure, may also be a suitable end connector 710. The connection stud may include a stem and a connector, where the stem includes a plurality of indentations or grooves defined along its axial length and the connector may be hook-shaped or otherwise turned about 180° from the axial direction of the stem.

[0060] Referring now to Figure 9, illustrated is another soil reinforcing element 900, according to one or more embodiments of the disclosure. The soil reinforcing element 900 may also be similar in some respects to the soil reinforcing element 700 of Figure 7. Accordingly, the soil reinforcing element 900 may be best understood with reference to Figure 7, where like numerals designate like components that will not be described again in detail. Unlike the soil reinforcing elements 700, 800 described above, the soil reinforcing element 900 does not have lead ends 706 that converge, but instead the longitudinal wires 704 remain generally parallel to each other along their entire length. Accordingly, the end connector 710 that attaches the soil reinforcing element 900 to a vertical facing is necessarily of a different configuration.

[0061] For example, the facing anchor assembly disclosed in co-owned U.S. Pat. App. No. 12/684,479 entitled "Wave Anchor Soil Reinforcing Connector and Method," filed January 8, 2010 and incorporated herein by reference to the extent not inconsistent with the present disclosure, may be a suitable end connector 710. The facing anchor assembly may include a pair of plates that are horizontally-disposed from each other and have a vertically- disposed tab at one end and define a trough at the other end. Interposed between the tab and the trough of each plate may be at least two longitudinally-offset transverse protrusions for capturing and seating at least two transverse wires 704. Another facing anchor assembly includes a one-piece device capable of receiving and securely seating at least one transverse wire 704, and simultaneously connecting to at least one horizontal wire of a vertical wire facing. The facing anchor may include a first side and a second side connected by a connecting member at one end, wherein the connecting member may includes a 180° turn in the facing anchor to define a gap between the first and second sides.

[0062] In other embodiments, the soil reinforcing element 900 may have upwardly extending extensions (not shown) disposed at its lead end. Such embodiments are described in co-owned U.S. Pat. App. No. 12/861 ,632 entitled "Soil Reinforcing Connector and Method of Constructing a Mechanically Stabilized Earth Structure," filed August 23, 2010 and incorporated herein by reference to the extent not inconsistent with the present disclosure. As described in the incorporated application, the upwardly extending extensions of the soil reinforcing element 900 may be coupled to a vertical wire facing using a connection device. The connection device includes a bearing plate having one or more longitudinal protrusions configured to seat the upwardly-extending extensions of the soil reinforcing element 900. The bearing plate may be configured to receive a threaded rod via a centrally-defined perforation. The rod may be extensible through the perforation and further through any adjacent vertical facings, and secured from removal by threading a nut onto its end.

[0063] In yet other embodiments, the end connector 710 may include a splice such as that disclosed in co-owned U.S. Pat. App. No. 12/887,907 entitled "Splice for a Soil Reinforcing Element or Connector," filed September 22, 2010 and incorporated herein by reference to the extent not inconsistent with the present disclosure. The splice may be used to lengthen the soil reinforcing element by coupling it to another soil reinforcing element or grid strip. The splice includes one or more wave plates, each wave plate including one or more transverse protrusions longitudinally-offset from each other and configured to receive one or more transverse wires 704 therein. Co-axially defined apertures in each wave plate are used to secure the wave plates together.

[0064] It will be appreciated by those skilled in the art that several different types of end connectors 710 (not specifically disclosed herein) may be used with the soil reinforcing elements 700, 800, 900 described herein, without departing from the scope of the disclosure.

[0065] The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

TBSS-056 CLAIMS I claim:

1 . A mechanically stabilized earth structure, comprising:

a vertical facing disposed adjacent an earthen formation;

a soil reinforcing element coupled to the vertical facing and extending into the earthen formation, the soil reinforcing element comprising a plurality of transverse wires coupled to at least two longitudinal wires having lead ends that converge and define a plurality of deformations thereon; and

an end connector welded to the lead ends of the longitudinal wires, the end connector being configured to couple the soil reinforcing element to the vertical facing.

2. The structure of claim 1 , wherein the soil reinforcing element is made of metal and the deformations are defined on the entire soil reinforcing element.

3. The structure of claim 1 , wherein the deformations are positively deformed deformations.

4. The structure of claim 3, wherein the positively deformed deformations are derived from cold-forming processing.

5. The structure of claim 1 , wherein the deformations are negatively deformed deformations.

6. The structure of claim 5, wherein the soil reinforcing element is made of rebar.

7. The structure of claim 1 , wherein the end connector is resistance welded to the lead ends.

8. The structure of claim 7, wherein the end connector comprises grooves configured to enhance the resistance weld.

9. The structure of claim 1 , wherein the end connector comprises a coil.

10. The structure of claim 9, wherein the end connector further comprises: TBSS-056 a threaded rod configured to extend through both the vertical facing and the coil, wherein a washer engages the vertical facing and prevents the threaded rod from passing completely therethrough; and

a nut threaded onto the threaded rod to prevent its removal from the coil.

1 1 . A method for coupling an end connector to a soil reinforcing element, where the soil reinforcing element has a plurality of transverse wires coupled to at least two longitudinal wires having lead ends that converge, comprising:

placing a portion of the end connector between the lead ends of the soil reinforcing element, the lead ends defining a plurality of deformations thereon; and

welding the portion of the end connector to the lead ends, whereby the plurality of deformations provides a more robust weld.

12. The method of claim 1 1 , wherein the end connector is resistance welded to the lead ends.

13. The method of claim 1 1 , wherein the end connector defines a plurality of grooves to enhance the resistance weld.

14. The method of claim 1 1 , wherein the deformations are positively deformed deformations derived from cold-forming processing.

15. The method of claim 1 1 , wherein the deformations are negatively deformed deformations.

16. A soil reinforcing element, comprising:

a pair of longitudinal wires extending substantially parallel to each other and having a connection end;

a plurality of transverse wires coupled to the pair of longitudinal wires and laterally- spaced from each other, the pair of longitudinal wires and the plurality of transverse wires being made of positively deformed wire or bar stock; and

an end connector coupled to the connection end. TBSS-056

17. The structure of claim 16, wherein the connection end comprises converging ends of the pair of longitudinal wires.

18. The structure of claim 17, wherein the end connector is resistance welded to the lead ends.

19. The structure of claim 18, wherein the end connector comprises a coil having a plurality of indentations defined thereon.